They are two of about 200 officers at the prison who have gone on strike in a protest over pay.

"It's not just about pay," they say. "We have a duty of care. While we are out here, we are not looking after the inmates - but we need to take this step to enable us to look after them better."

The pair have a real insight into the "unglamorous" and "dangerous" world they inhabit, and they talk about the inmates and what they see as a crisis in the prison service with eloquence and sincerity.

'Decent lads'

"We are the forgotten service," says Mr Richards.

"The police are visible, we are not. We are behind walls and no-one knows what goes on."

Mr Stone, 30, who has been at Wormwood Scrubs for his entire seven-year prison officer career, says the problem is not the inmates, who are mostly "decent enough lads".

"The Prison Service is always quoting that we are here to look after those lads with decency and humanity - but we cannot do that without resources," he says.

We don't want to be standing out here, but we are making a point for the staff and the inmates

Luke Stone

"There is less and less staff to look after them and that becomes dangerous.

"Their frustrations come to the surface and they have no-one to take it out on other than us and other inmates."

Both men complain about not having enough time to talk to inmates, to get to know them and their needs.

They nod knowingly when asked if prisons have become more violent.

'Ticking boxes'

Mr Stone talks of being kicked, punched, head-butted as though it were commonplace.

They both list incidents where officers have been stabbed with broken bottles and home-made knives.

"There has also been an increase in prisoner on prisoner attacks," Mr Stone says.

"Bullying and self harm are major problems, and suicides in custody are more common than ever. We just don't have the staff to stop the bullying."

Most of the 1,258 inmates are likely to have been charged with robbery, burglary or sexual offences.

Many are put to work in the laundry or making headphones for airlines, and they can also access workshops and education.

Jail is no longer a deterrent - for the vast majority it's an occupational hazard

Mark Richards

But Mr Richards, 34, who has worked at the prison for seven-and-a-half years says they need to be taught trades, such as plumbing or bricklaying.

He says: "There is not a lot for them to do. The workshops aren't constructive. It ticks all the right boxes, but they are not learning."

The pair say all of this is happening against a backdrop of improved conditions.

Aside from the overcrowding and fewer staff to look after the increased number of inmates - prisoners have everything they could possibly want, according to the pair, and that is half the problem.

'Necessary evil'

Both men laugh at the government's so-called "tough stance" on crime.

They say the system is "absolutely soft", with everything - from televisions to canteen access - guaranteed.

"Some prisoners talk of the old days, when there was discipline and they had to earn everything they got," says Mr Stone.

"And when you reward everyone, there is nothing to strive for. You have already fed the donkey the whole carrot. "

Mr Richards adds: "Jail is no longer a deterrent - for the vast majority it's an occupational hazard. The system is failing them."

The burly men know they are only small cogs in a big wheel and say more needs to be done to get prisoners into decent housing and employment.

They both also talk generally of a breakdown of society and say some of the younger inmates "really do not know right from wrong".

As senior officers, they earn £33,500 a year, inclusive of London weighting, but they say the below inflation rises equate to pay cuts.

"We are just turnkeys," says Mr Richards. "A necessary evil."

"We don't want to be standing out here, but we are making a point for the staff and the inmates," adds Mr Stone.